Bearing assembly

ABSTRACT

The invention relates to a bearing assembly providing a bearing having a first ring with a hole, two front edges and an outer cylindrical surface, and a second ring having a hole, two front edges and an outer cylindrical surface, the first and second rings being relatively in relative rotation about a central axis. At least one row of rolling elements is housed in a bearing chamber formed between an outer cylindrical surface and a hole of the rings. The assembly is configured to be mounted in a housing. The assembly also includes at least one envelope mounted on one of the rings of the bearing, such that a dimensional difference between the housing and the bearing is compensated by the envelope.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to French patent application no.1557244 filed on Jul. 29, 2015, the contents of which are fullyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an assembly comprising a bearing.

BACKGROUND OF THE INVENTION

A bearing usually provides an inner ring and an outer ring, the ringsbeing in rotation relative to one another. The rings may together form abearing chamber containing the rolling elements, such as balls, needlesor rollers.

A bearing is designed to be mounted in a housing of a mechanical systembetween a static mechanical element and a mechanical element moveable inrotation such as to support the relative rotation of same.

The design of a bearing, and more specifically the type of bearing, thenumber of rows of rolling elements, the type of rolling elements, andthe dimensioning of the rings and of the rolling elements, depends onthe intended application of the mechanical system. The conditionsrelating to torque, rotational speed, load, environment and even thespace available inside the housing affect the bearing and thereforeconstitute design constraints on same.

BRIEF SUMMARY OF THE INVENTION

However, manufacturers of mechanical systems and/or bearings may changetheir ranges and lose compatibility.

Although the features of bearings have been improved, bearings stillhave the same seat, and a smaller seat could be beneficial.

It is known from JP-U-S61 35222 to provide a bearing assembly with anenvelope mounted on the outer ring of the bearing. Such an envelope canenable compensation of a dimensional difference between the housing andthe bearing. According to the prior art, the envelope includes distinctfirst and second envelope parts, each part having an annular flange atleast partially overlapping a front edge of the ring, and a cylindricalportion extending from the flange and at least partially overlapping thecylindrical surface or hole of the ring outside the bearing chamber, thetwo envelope parts being rigidly connected to one another by attachmentmeans provided on the cylindrical portions. The attachment means provideat least one cavity formed at one end portion of the cylindrical portionof the first envelope part and at least one relief formed at one endportion of the cylindrical portion of the second envelope part, therelief being housed in the related cavity to attach the first and secondenvelope parts.

The cavity in the first envelope part and the relief in the secondenvelope part are annular. One drawback of such an arrangement is thatrelative rotation between the two envelope parts may occur.

The ends of the envelope parts need to be deformed to seat the relief onthe second envelope part inside the cavity in the first envelope part.The ends are difficult to deform radially on account of the annularshape of same.

The invention is in particular intended to address these problems byproposing a bearing assembly that is simple to make and to assemble, andthat is modular in terms of use and adaptation to numerous applications.

For this purpose, the invention relates to a bearing assembly comprisinga bearing provided with a first ring having a hole, two front edges andan outer cylindrical surface, and a second ring having a hole, two frontedges and an outer cylindrical surface. The first and second rings maybe in relative rotation about a central axis. The bearing also includesat least one row of rolling elements housed in a bearing chamber formedbetween an outer cylindrical surface and a hole of the rings. Theassembly is designed to be mounted in a housing.

The assembly includes at least one envelope mounted on one of the ringsof the bearing, such that a dimensional difference between the housingand the bearing is compensated by the envelope. The envelope includesdistinct first and second envelope parts, each part having an annularflange at least partially overlapping a front edge of the ring, and acylindrical portion extending from the flange and at least partiallyoverlapping the cylindrical surface or hole of the ring outside thebearing chamber, the two envelope parts being rigidly connected to oneanother by attachment means provided on the cylindrical portions. Theattachment means provide at least one cavity formed at one end portionof the cylindrical portion of the first envelope part and at least onerelief formed at one end portion of the cylindrical portion of thesecond envelope part, the relief being housed in the related cavity toattach the first and second envelope parts.

According to the invention, the annular end portion of the cylindricalportion of the first envelope part includes a plurality of reliefs andcavities spaced out regularly, successively and alternately about thecircumference. The annular end portion of the cylindrical portion of thesecond envelope part includes a plurality of reliefs and cavities spacedout regularly, successively and alternately about the circumference.

Thanks to the invention, the difference between the dimensions betweenthe bearing and the housing in which the bearing is designed to bemounted is compensated by the thickness of the envelope rigidlyconnected to one of the rings. More specifically, the flanges and thecylindrical portions of the envelope parts act as bearing surfaces withthe housing in place of the front edges and the outer cylindricalsurfaces of the bearing.

A standard small bearing can be adapted to other applications withouthaving to modify the whole mechanical system. This helps to reduce thetime and cost related to designing the mechanical system. Furthermore,if the dimensions of the housing are outside a predetermined range, astandard bearing from the range can be adapted.

The invention also makes it possible to adapt small bearings in place oflarger bearings, while incorporating additional functions using theflanges.

Another advantage is that no modifications are made to the standardbearing. The envelope is mounted on the rings after the bearing has beendesigned and manufactured. The envelope is mounted on the outside of thebearing.

Furthermore, once the envelope has been assembled, the reliefs andcavities are circumferentially adjacent to one another. Since theattachment means are found alternately on two separate envelope parts,the attachment means thus formed provide an anti-rotation functionbetween the two portions of the envelope.

Assembling the two envelope parts on a ring is relatively simple for anoperator since he need simply position same manually or mechanically onthe ring to insert one relief of one of the portions into a relatedcavity of the other portion. The two parts are then rigidly connectedtogether and cannot be removed from the ring. The envelope parts canthen be assembled at the site where the bearing is manufactured, thenthe assembly is transported to the manufacturer of the application orassembled directly at the site where the application is manufactured.

According to advantageous but optional aspects of the invention, such abearing assembly may include one or more of the following features inany technically admissible combination:

-   -   The rolling elements are spaced out regularly about the        circumference, and held by a cage.    -   The rolling elements are balls.    -   The first and second rings of the bearing are solid.    -   The rings and the rolling elements determine a pitch diameter of        the bearing that is parallel to the axis of relative rotation of        the first and second rings of the bearing.    -   The rings and the rolling elements determine a pitch diameter of        the bearing that is perpendicular to the axis of relative        rotation of the first and second rings of the bearing.    -   The envelope includes at least one layer of material made of a        vibration-damping material.    -   The envelope includes at least one layer of electrically        insulating material to prevent electrical currents from passing        through the bearing.    -   The envelope is made of a plastic or synthetic material.    -   At least one flange of the envelope mounted on the first ring is        in sliding contact with the other ring, either directly against        one of the surfaces of the second ring or indirectly against an        element rigidly connected to the second ring.    -   The assembly includes two envelopes fitted to each of the rings        of the bearing.    -   The two envelopes fitted to each of the rings of the bearing are        in sliding contact via the flanges of same in pairs such as to        ensure that the bearing is completely sealed.    -   The cylindrical portions of the two parts of the envelope are        annular and overlap the entire cylindrical surface or the hole        of the ring.    -   The shapes of the relief and of the related cavity match one        another.    -   The relief is a bead that is rounded or beveled to facilitate        insertion of same.    -   The end portions of the cylindrical portions of the first and        second envelope parts bearing the at least one relief and the at        least one cavity overlap one another.    -   The thicknesses of the end portions of the cylindrical portions        of the first and second envelope parts bearing the at least one        relief and the at least one cavity are strictly less than the        rest of the cylindrical portions, such as to form shoulders.    -   The edges of each of the cylindrical portions of the first and        second envelope parts come into contact with the shoulders on        the other envelope part.    -   The annular end portions provided with a plurality of reliefs        and cavities successively and alternately of the cylindrical        portions of the first and second envelope parts are        circumferentially adjacent.    -   Each end portion provided with a relief of the first and second        envelope parts is circumferentially adjacent to a single end        portion provided with a cavity, a spacing zone being formed        between two successive relief-cavity pairings.    -   The end portion of the cylindrical portion of the first envelope        part includes a plurality of tabs.    -   The end portion of the cylindrical portion of the second        envelope part includes a plurality of tabs.    -   All of the tabs of the cylindrical portion of the first envelope        part have cavities.    -   All of the tabs of the cylindrical portion of the second        envelope part have cavities.    -   Successive tabs of the two envelope parts are provided        alternately with a relief and a cavity.    -   Successive tabs of the two envelope parts provided alternately        with a relief and a cavity are circumferentially adjacent.    -   The tabs are regularly distributed around the circumference.    -   The tabs extend from the cylindrical portion towards the other        envelope part.    -   An end portion of a first envelope part includes at least one        attachment means comprising a relief and an end portion of a        second envelope part includes at least one attachment means        comprising a cavity, at least one of the end portions having at        least one spacing zone adjacent to an end portion provided with        one of the attachment means.    -   The cavities have a flared edge to facilitate insertion of the        reliefs.

The invention also relates to a method for assembling a bearing assemblyaccording to a specific embodiment of the invention, comprising thefollowing steps:

-   -   (a) A bearing is assembled in advance,    -   (b) Two envelope parts are positioned coaxially and on either        side of one of the rings of the bearing, an end portion of a        first envelope part including at least one attachment means        comprising a relief and an end portion of a second envelope part        including at least one attachment means comprising a cavity, at        least one of the end portions having at least one spacing zone        circumferentially adjacent to an end portion provided with a        cavity on one side and to an end portion provided with a relief        on the other side,    -   (c) The end portion of one of the envelope parts slides axially        onto at least one spacing zone of the other envelope part such        that the end portion overlaps the spacing zone radially,    -   (d) A relative rotation about the axis is applied to the        envelope parts such as to slide the end portion including at        least one attachment means of one of the envelope parts in        rotation from the spacing zone towards the end portion including        at least one attachment means of the other envelope part, and    -   (e) The attachment means of the envelope parts cooperate with        one another.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The invention and other advantages thereof are set out more clearly inthe description below of embodiments of a bearing assembly according tothe principle of the invention, which are provided purely as examplesand with reference to the non-drawings attached, in which:

FIG. 1 is a cross-sectional view of a bearing assembly according to afirst embodiment,

FIG. 2 is a front view of the bearing assembly according to the firstembodiment,

FIG. 3 is a side view of the bearing assembly according to the firstembodiment,

FIGS. 4a and 4b are the cross-sectional views II-II and III-IIIrespectively of details of an envelope of a bearing assembly accordingto the first embodiment,

FIG. 5 is a side view of a first bearing assembly position according toa second embodiment,

FIG. 6 is a side view of a second bearing assembly position according tothe second embodiment,

FIG. 7 is a side view of a third bearing assembly position according tothe second embodiment,

FIGS. 8a, 8b and 8c are the cross-sectional views IV-IV, V-V and VI-VIrespectively of details of an envelope of a bearing assembly accordingto the second embodiment,

FIG. 9 is a side view of a bearing assembly according to a thirdembodiment, and

FIG. 10 is a side view of a bearing assembly according to a fourthembodiment.

DETAILED DESCRIPTION OF THE INVENTION

An assembly A includes a bearing 1 with a central axis of rotation X1including an outer ring 2, an inner ring 3, a row of rolling elements 4,in this case balls, arranged in parallel planes and held respectively bya cage 5. Such an assembly is designed to be mounted in a housingprovided in a mechanical system (not shown).

The rings 2, 3 are coaxial to the central axis X1 in normal operatingmode.

The outer ring 2 has an outer cylindrical surface 21 and a hole 22 inwhich a race is formed for the rolling elements 4.

The inner ring 3 has an outer cylindrical surface 31 in which a race isformed for the rolling elements 4.

The inner ring 3 may be in relative rotation and the outer ring 2 non-inrelative rotation or vice versa, or both rings may be in relativerotation in relation to the other about the central axis X1.

The outer ring 2 is delimited axially by two front radial edges 23 and24 and the inner ring 3 is delimited axially by two front radial edges33 and 34 such that the edges are respectively aligned axially to definean axial dimension of the bearing 1.

The inner ring 3 also has a cylindrical through-hole 32. For example, ashaft or supporting element may be inserted into the hole 32. The hole32 in the inner ring 3 and the outer cylindrical surface 21 of the outerring 2 define a radial dimension of the bearing.

The outer cylindrical surface 31 of the inner ring 3, the hole 22 of theinner ring 2 and the front radial edges 23, 33 and 24, 34 form a bearingchamber 8 within which the rolling elements 4 move between the rings 2,3. The bearing chamber 8 may be filled with lubricant, for examplegrease or oil, to reduce friction between the contact surfaces of themoving elements, in this case the rolling elements 4, the race formed onthe outer cylindrical surface 31 and the race formed in the hole 22 inthe inner ring 2.

The rings 2, 3 and the rolling elements 4 determine a pitch diameter P1of the bearing 1 that is an axis of rotation of the rolling elements,the rings being in relative rotation parallel to this axis locatedbetween the rings.

According to the embodiment shown in FIGS. 1 to 10, the pitch diameterP1 is parallel to the central axis of rotation X1. According to analternative not shown, the pitch diameter P1 may be perpendicular to thecentral axis.

According to the invention, the assembly A also includes an envelope 10mounted on the outer ring 2.

The envelope 10 includes a first envelope part 11 and a second envelopepart 13 that are distinct, each having an annular flange 11 a, 13 a atleast partially overlapping a front edge 23, 24 respectively of theouter ring 2.

The first and second envelope parts 11, 13 each have a cylindricalportion 11 c, 13 c respectively extending axially from the flange 11 a,11 b towards the other envelope part.

The cylindrical portions 11 c, 13 c each overlap a portion of the outercylindrical surface 21 of the outer ring 2.

The two parts 11, 13 of the envelope 10 are rigidly connected togetherusing attachment means 15 provided on the cylindrical portions 11 c, 13c.

The attachment means 15 provide a cavity 11 e formed at one end portionof the cylindrical portion 11 c of the first envelope part 11 and arelief 13 e formed at one end portion of the cylindrical portion 13 c ofthe second envelope part 13.

According to a first embodiment illustrated in FIGS. 1, 2, 3, 4 a and 4b, the end portions of the first and second envelope parts 11, 13provide pluralities of tabs 16, 17, 18, 19.

The end portion of the cylindrical portion 11 c of the first envelopepart 11 includes a plurality of tabs 18, each having a cavity 18 a.Between two successive tabs 18, the end portion of the cylindricalportion 11 c includes in each instance a tab 19 provided with a relief19 a. The tabs 18 and 19 are thus adjacent and alternate with a relief19 a or a cavity 18 a.

Furthermore, the thickness of the tabs 18 and 19 is less than thethickness of the rest of the cylindrical portion 11 c.

The tabs 18 extend the outer cylindrical surface of the cylindricalportion 11 c and are located towards the outside of the envelope part11. The tabs 19 extend the inner cylindrical surface of the cylindricalportion 11 c and are located towards the inside of the envelope part 11.

The end portion of the cylindrical portion 13 c of the second envelopepart 13 includes a plurality of tabs 16, each having a relief 16 a.Between two successive tabs 16, the end portion of the cylindricalportion 13 c includes in each instance a tab 17 provided with a cavity17 a. The tabs 16 and 17 are thus adjacent and alternate with a relief16 a or a cavity 17 a.

Furthermore, the thickness of the tabs 16 and 17 is less than thethickness of the rest of the cylindrical portion 13 c.

The tabs 16 extend the outer cylindrical surface of the cylindricalportion 13 c and are located towards the outside of the envelope part13. The tabs 17 extend the inner cylindrical surface of the cylindricalportion 13 c and are located towards the inside of the envelope part 13.

The tabs 16 of the second envelope part 13 radially overlap the tabs 18of the first envelope part 11, the reliefs 16 a being housed in thecavities 18 a. Similarly, the tabs 19 of the first envelope part 11radially overlap the tabs 17 of the second envelope part 13, the reliefs19 a being housed in the cavities 17 a. According to an alternative notshown, the tabs provided with reliefs may be radially overlapped by tabsprovided with cavities.

The shapes of the reliefs 16 a, 19 a and of the related cavities 18 a,17 a match one another.

Each relief 16 a, 19 a is an annular bead that is rounded to facilitatethe axial sliding of the relief 16 a, 19 a along the end portion of theother envelope during assembly of the two envelope parts 11, 13.According to a variant not shown, the reliefs may have a beveled facedesigned to facilitate insertion.

The engagement of each relief 16 a, 19 a on the end portion of the otherenvelope is enabled by deformation of the tab 16, 19 bearing the relief16 a, 19 a.

The sum of the thicknesses of the related tabs 16, 18 and 17, 19 isequal to the thickness of the rest of the cylindrical portions 11 c, 13c, thereby forming a substantially cylindrical outer surface of theenvelope 10, enabling the assembly to be housed in a standard seat.

The reliefs 16 a, 19 a housed in the cavities 18 a, 17 a respectivelyenable the rigid axial attachment of the parts 13, 11 of the envelope10.

Furthermore, once the envelope 10 has been assembled, the tabs 16, 19and 17, 18 are circumferentially adjacent to one another. Since theattachment means belong alternately to the two distinct parts 11, 13,the attachment means 15 formed by the tabs 16, 17, 18, 19 prevent therelative rotation between the parts 11, 13 of the envelope 10.

The parts 11, 13 of the envelope 10 may be made of a plastic orsynthetic material. The parts include at least one layer of materialmade of a vibration-damping material. The parts may also include atleast one layer of electrically insulating material to preventelectrical currents from passing through the bearing.

The difference between the axial dimensions between the bearing 1 andthe housing in which the assembly A is designed to be mounted iscompensated by the envelope 10.

According to the embodiment, the assembly A also includes two annularflanges 12, 14 mounted on the radial edges 33, 34 respectively of theinner ring 3.

The flanges 12, 14 are rigidly connected to the inner ring 3 usingattachment means (not shown), for example by welding, gluing, molding,cooperation of mechanical means such as parts of the flange and of thering cooperating by shape, or any other appropriate means.

The free ends 11 b, 13 b of the flanges 11 a, 13 a of the envelope 10mounted on the outer ring 2 are in sliding contact with the free ends 12a, 14 a of the flanges 12, 14 of the inner ring 3. Contact is made atthe pitch diameter P1 of the bearing 1. The bearing chamber 8 is sealedby the envelope 10 and the annular flanges 12, 14.

A second embodiment illustrated in FIGS. 5, 6, 7, 8 a, 8 b and 8 c, inwhich identical elements are indicated using the same reference signs,differs from the first embodiment in that the tabs 25, 26 extend fromthe cylindrical portions 11 c, 13 c towards the other envelope part 13,11 respectively.

The end portion of the cylindrical portion 11 c of the first envelopepart 11 includes a plurality of tabs 25, each having a relief 25 a. Thereliefs 25 a are shown transparently in FIGS. 5 to 7 using broken linesin order to facilitate understanding of the embodiment of the invention.

The tabs 25 each extend axially from the cylindrical portion 11 ctowards the other envelope part 13 via a tab end 25 b. The tab ends 25 bare thinner than the rest of the cylindrical portion 11 c. The tab ends25 b are provided with reliefs 25 a. The tabs 25 are regularly spacedout about the circumference.

The tabs 25 extend the outer cylindrical surface of the cylindricalportion 11 c and are located towards the outside of the envelope part11.

A recess 27 is formed between two successive tabs 25. The tab ends 25 bextend axially beyond the edges of the recesses 27.

The recesses 27 are thinner than the rest of the cylindrical portion 11c, extend the inner cylindrical surface of the cylindrical portion 11 cand are located towards the inside of the envelope part 11.

Each recess 27 has a cavity 27 a adjacent to a first tab 25 and aspacing zone 27 b circumferentially adjacent to the cavity 27 a on oneside and to a second tab 25 on the other side.

Similarly to the first envelope part 11, the cylindrical portion 13 c ofthe second envelope part 13 includes a plurality of tabs 26 providedwith reliefs 26 a at the ends of the tabs 26 b.

Between two successive tabs 26, the cylindrical portion 13 c includes arecess 28 provided with a cavity 28 a and a spacing zone 28 b.

In the assembled position of the parts 11, 13 of the envelope 10, thetab ends 25 b of the first envelope part 11 radially overlap therecesses 28 of the second envelope part 13 causing the reliefs 25 acarried on the tab ends 25 b to be housed in the cavities 28 a of therecesses 28. Similarly, the tab ends 26 b of the second envelope part 13radially overlap the recesses 27 of the first envelope part 13 causingthe reliefs 26 a carried on the tab ends 26 b to be housed in thecavities 27 a of the recesses 27.

The sum of the thicknesses of the tab ends 25 b, 26 b related to therecesses 28, 27 respectively is equal to the thickness of the rest ofthe cylindrical portions 11 c, 13 c, thereby forming a substantiallycylindrical outer surface of the envelope 10, enabling the assembly tobe housed in a standard seat.

The assembly method of an assembly A fitted with an envelope 10 havingtwo parts 11, 13 according to the second embodiment of the inventionincludes the following successive steps, as illustrated in FIGS. 5 to 7.

A bearing 1 is assembled in advance.

Two envelope parts 11, 13 are positioned coaxially about the centralaxis X1 on either side of the outer ring 2 of the bearing 1.

The tab ends 25 b of the first envelope part 11 slide axially onto thespacing zones 28 b such that the tab ends 25 b radially overlap thespacing zone 28 b until stopped by the back edge of the recess 28.Similarly, the tab ends 26 b of the second envelope part 13 slideaxially onto the spacing zones 27 b until stopped by the back edge ofthe recess 27.

A relative rotation about the central axis X1 is applied to the firstand second envelope parts 11, 13 such as to cause the tab ends 25 bbearing the reliefs 25 a to slide in rotation towards the cavities 28 aof the recesses 28, and the tab ends 26 b bearing the reliefs 26 a toslide in rotation towards the cavities 27 a of the recesses 27.

The relative rotation is performed until the reliefs 25 a, 26 a arecompletely housed in the cavities 27 a, 28 a respectively.

In the assembled position, the spacing zones 27 b and 28 b, which areused for the initial insertion of the tabs 25, 26 before the finalpositioning of same, are arranged in axially adjacent pairs, formingrecess portions.

The assembly method described above may be adapted without limitationfor other embodiments of the invention. For example, a similar methodmay be implemented for an assembly A according to the first embodimentwith a plurality of regularly spaced reliefs 13 e and cavities 11 e.

A third embodiment, illustrated in FIG. 9, in which identical elementsare indicated using the same reference signs, differs from the secondembodiment in that the cavities 27 a, 28 a each have a flared edge 27 c,28 c to facilitate insertion of the reliefs 26 a, 25 a respectivelyduring the relative rotation of the envelope parts 11, 13.

The cavities 27 a, 28 a are provided with flared edges 27 c, 28 c in thedirection of insertion of the respective reliefs 26 a, 25 a.

A fourth embodiment, illustrated in FIG. 10, in which identical elementsare indicated using the same reference signs, differs from the firstembodiment in that the assembly A is provided with an outer envelope 10mounted on the outer ring 2 of the bearing 1 and an inner envelope 40mounted on the inner ring 3 of the bearing 1.

The outer envelope 10 is as disclosed in any one of the embodiments oralternatives described above.

The inner envelope 40 includes a first envelope part 42 and a secondenvelope part 44 that are distinct, each having an annular flange 42 a,44 a at least partially overlapping a front edge 33, 34 respectively ofthe inner ring 3.

The first and second envelope parts 42, 44 each have a cylindricalportion 42 c, 44 c respectively extending axially from the flange 42 a,44 a towards the other envelope part.

The cylindrical portions 42 c, 44 c each overlap a portion of the hole32 in the inner ring 3.

The two parts 42, 44 of the inner envelope 40 are rigidly connectedtogether using attachment means 45 provided on the cylindrical portions42 c, 44 c.

The attachment means 45 are as disclosed in any one of the embodimentsor alternatives described above.

The outer circumferential edges 42 b, 44 b of the flanges 42, 44respectively of the inner envelope 40 mounted on the inner ring 3 of thebearing 1 come into sliding contact with the inner circumferential edges11 b, 13 b of the flanges 11, 13 respectively of the outer envelope 10mounted on the outer ring 2 of the bearing 1.

During relative rotation of the inner and outer rings 3, 2 of thebearing 1, the edges 42 a and 11 b, 44 a and 13 b remain in contact andslide on one another.

According to embodiments not shown, the bearing may have one or morerows of rolling elements. The rolling elements may be balls, rollers,needles or any other type of rolling element.

The technical features of the embodiments and variants provided forabove may be combined.

The invention claimed is:
 1. A bearing assembly configured to be mountedin a housing, comprising: a bearing provided with: a first ring having ahole, two front edges and an outer cylindrical surface, a second ringhaving a hole, two front edges and an outer cylindrical surface, thefirst and second rings being in relative rotation about a central axis(X1), and at least one row of rolling elements housed in a bearingchamber formed between an outer cylindrical surface and a hole of therings, at least one envelope mounted on one of the rings of the bearing,such that: a dimensional difference between the housing and the bearingis compensated by the envelope, the envelope includes a first envelopepart and a second envelope part that are distinct, each having anannular flange at least partially overlapping a front edge of the ringand a cylindrical portion extending from the flange and at leastpartially overlapping the cylindrical surface or hole of the ringoutside the bearing chamber, the two envelope parts are rigidlyconnected together using attachment means provided on the cylindricalportions, and the attachment means provide at least one cavity formed atone end portion of the cylindrical portion of the first envelope partand at least one relief formed at one end portion of the cylindricalportion of the second envelope part, the at least one relief beinghoused in the related cavity to attach the first and second envelopeparts the assembly (A), wherein the annular end portion of thecylindrical portion of the first envelope part includes a plurality ofreliefs and cavities spaced out regularly, successively and alternatelyabout the circumference, and wherein the annular end portion of thecylindrical portion of the second envelope part includes a plurality ofreliefs and cavities spaced out regularly, successively and alternatelyabout the circumference, wherein at least one envelope part is providedwith at least one spacing zone that is circumferentially adjacent to theend portion provided with the at least one cavity on one side and to theend portion provided with the at least one relief on the other side. 2.The bearing assembly according to claim 1, wherein at least one flangeof the envelope mounted on the first ring is in sliding contact with theother ring, either directly against one of the surfaces of the secondring or indirectly against an element rigidly connected to the secondring.
 3. The assembly according to claim 1, wherein the one end portionof the cylindrical portion of the first envelope part comprise aplurality of tabs toward the second envelope part, and wherein the atleast one cavity formed at the one end portion of the cylindricalportion of the first envelope part resides between a pair of theplurality of tabs.
 4. The bearing assembly according to claim 1, whereinthe annular end portions provided with a plurality of reliefs andcavities successively and alternately of the cylindrical portions of thefirst and second envelope parts are circumferentially adjacent.
 5. Amethod for assembling a bearing assembly (A) including at least oneenvelope part having at least one spacing zone that is circumferentiallyadjacent to an end portion provided with a cavity on one side and to anend portion provided with a relief on the other side, the methodcomprising: providing a pre-assembled bearing including rings thatrotate relative to a central axis (X1), positioning the at least oneenvelope part coaxially and on either side of one of the rings of thebearing, an end portion of a first envelope part of the at least oneenvelope part including at least one attachment means comprising therelief and an end portion of a second envelope part of the at least oneenvelope part including at least one attachment means comprising thecavity, at least one envelope part having at least one spacing zone thatis circumferentially adjacent to the end portion provided with thecavity on one side and to the end portion provided with the relief onthe other side, sliding axially onto at least one spacing zone of theother envelope part the end portion of one of the envelope parts suchthat the end portion overlaps the spacing zone radially, sliding the endportion including at least one attachment means of one of the envelopeparts in rotation from the spacing zone towards the end portionincluding at least one attachment means of the other envelope part byapplying a relative rotation about the axis (X1) to the envelope parts,and wherein the attachment means of the envelope parts cooperating withone another.